Mammography systems and methods, including methods utilizing breast sound comparision

ABSTRACT

Provided are systems using compression devices for a mammography unit, and methods of using the same, for example, in conjunction with imaging of a patient&#39;s breast. The instant mammography units can comprise at least one x-ray transparent inflatable chamber for containing a fluid. When fluid is introduced into the chamber, at least one surface of the chamber expands, breast motion is limited, and the breast and its vasculature are compressed. Fluid may also be released from the chamber, and as the chamber deflates, blood flow to the breast is restored, producing Korotkoff sounds that may be detected by a sound detection device. Sound data may be obtained with respect to both of a patient&#39;s breasts, and the sound data from a patient&#39;s first breast may be compared with the data obtained from the contralateral breast. The detected sounds, the comparison data, or both may be used to assist a radiologist in identifying regions of interest on a mammogram, and additionally or alternatively may be used to a enhance a computer-assisted detection (CAD) process by contributing additional data parameters.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Ser. No. 11/752,142,filed May 22, 2007, which is a continuation-in-part of U.S. Ser. No.11/279,280, filed Feb. 11, 2006 (now U.S. Pat. No. 7,248,668) and acontinuation-in-part of U.S. Ser. No. 11/582,243, filed Oct. 17, 2006(now U.S. Pat. No. 7,251,309), which is a continuation of U.S. Ser. No.11/246,419, filed Oct. 7, 2005 (now U.S. Pat. No. 7,142,631), which is acontinuation-in-part of U.S. Ser. No. 10/748,891, filed Dec. 30, 2003(now U.S. Pat. No. 6,975,701), each of which are herein incorporated byreference in their entirety.

FIELD OF THE INVENTION

The present inventions relate to the field of radiology and particularlyto mammography. More particularly, the present inventions relate tomammography compression systems, and methods of their use.

BACKGROUND OF THE INVENTION

Mammography is the process of obtaining x-ray images of the human breastfor diagnosis or surgery. It involves positioning a patient's breast ina desired orientation against a cassette holder (also known as a“bucky”) of a mammography unit, compressing the breast with acompression device (e.g., a compression paddle), and then exposing thebreast to x-rays to create a latent image of the breast on an imagereceptor. After exposure, the compression device is released. An exampleof the image receptor is a film in contact with an intensifying screencontained within a cassette. The cassette is inserted into the cassetteholder before every image is taken and removed after every image. Thefilm is removed from the cassette and developed to produce aradiographic image of the breast. Another type of image receptor is asolid state device, and the image is obtained electronically.

A complete mammographic study usually involves at least two x-rayexposures of each breast. One exposure is a craniocaudal view in whichthe breast is compressed in a superior-inferior direction, i.e., fromthe direction of the patient's head downward, against a tube-sidesurface of the cassette holder. The plane of the tube-side surface ofthe cassette holder is parallel to the floor and the x-ray beam isdirected vertically downward. A second exposure is a lateral or obliqueview in which the breast is compressed mediolaterally, i.e., from thedirection of the patient's midline sidewise, against the tube-sidesurface of the cassette holder which is angled, along with the axis ofthe x-ray beam, relative to the floor.

Typically, the compression device is a compression paddle, whichincludes a rectangular flat plate that is attached to the mammographyunit between an x-ray tube assembly and the bucky. The edges of thepaddle are usually turned upward away from the bucky to provide a smoothcurved surface for patient comfort. The compression paddle is usuallymade of thin, light-transparent, plastic that absorbs only a smallfraction of the incident x-ray beam. The compression paddle is movedeither manually or by power drive to apply a compression force to thebreast, thereby limiting breast motion and flattening the breast againstthe cassette holder to a near uniform thickness to improve imagequality. U.S. Pat. No. 6,049,583 issued to the present inventordiscusses methods and apparatus for measuring compression force inmammography. During compression, parts of the patient's body come intocontact with the compression paddle. After x-ray exposure, thecompression force is released for patient comfort.

As is well known in the field, to properly position the breast, thepatient's chest wall or other regions of the body, depending on thedesired view, are brought into tight contact with the rigid surfaces ofthe cassette holder, its edges, and corners. This procedure has theeffect of forcing the patent's anatomy to contour to the shape of thecassette holder, which often causes patient discomfort and pain.Oftentimes, overlapping internal structures are present within thebreast tissue that can obscure their delineation in a radiographicimage. As a result, it is often necessary to reposition the breastslightly in order to arrive at a diagnosis. This requires repositioningthe patient for each view with the attendant discomfort due in part torepeat compressions. U.S. Pat. No. 6,850,590 by the present inventor,incorporated herein by reference, discusses methods of reshaping thebreast without repositioning.

It is well known that many women find the procedure for compressing thebreast to be uncomfortable and for some, even painful. Methods toprovide patient comfort during this procedure involve adding cushioningmaterial to the patient contact surfaces of the compression paddle.Examples are described in U.S. Pat. Nos. 6,577,702 and 6,968,033 issuedto Lebovic et al.; and U.S. Pat. No. 6,765,984 issued to Higgins, et al.Also, U.S. Pat. No. 6,975,701 and U.S. Patent Publication No.2006/0050844 by the present inventor, each of which is incorporatedherein by reference, describe cushioning devices for compressionpaddles. U.S. Pat. No. 5,479,927, issued to Shmulewitz discusses a gelpad attached to the patient-contact surface of the compression paddle.

To properly position the patient's breast in a desired orientationbefore exposure, a technologist is guided by a light beam originatingfrom the x-ray tube assembly that passes through a collimator and thecompression paddle to illuminate the area of the bucky that will beexposed to x-rays, i.e., the imaging area. Sometimes, adding cushioningmaterials to compression paddles blocks the light and impedes properpositioning of the breast.

Other attempts to resolve problems with the compression paddle haveincluded redesigning the shape of the paddle or its angulation, e.g.,U.S. Pat. Nos. 4,962,515; 5,199,056; 5,506,877; 5,706,327; 6,974,255.

Angiogenesis plays an important role in the development of breastcarcinoma. The use of contrast and molecular imaging agents to detectand/or treat breast cancer also relies on breast vascularity.Unfortunately, traditional mammography systems that exert staticcompression force on a breast that is positioned between a bucky and acompression paddle are incompatible with studies relating to blood flowduring mammography screening, as the static compression force at leastpartially interrupts blood flow within the breast.

A recent study concluded that the use of computer-aided detection (CAD)in mammography is associated with reduced accuracy of interpretation ofscreening mammograms, and furthermore that the increased rate of biopsywith the use of computer-aided detection is not clearly associated withimproved detection of invasive breast cancer. Fenton J J et al., N EnglJ. Med. 2007 Apr. 5; 356(14):1399-409.

There remains a great need for devices and methods to compress apatient's breast during mammography that can minimize or eliminate thepain and discomfort experienced by the patient. There also exists a needfor devices and methods that can compress a patient's breast but thatare not incompatible with studies relating to blood flow duringmammography. Improvements to CAD sensitivity and specificity duringmammography could reduce incidence of unnecessary biopsies, but suchimprovements have not yet been developed.

SUMMARY OF THE INVENTION

Provided are mammography units, and methods of using the same, forexample, in conjunction with imaging of a patient's breasts. Themammography units can compress a breast without the need for atraditional compression paddle, or can compress the breast using atraditional compression paddle in conjunction with a novel compressiondevice. Specialized devices for use with the instant mammography unitscan comprise at least one x-ray transparent inflatable chamber forcontaining a fluid, for example, a pressurized gas. When fluid isintroduced into the chamber, at least one surface of the chamberexpands. As the chamber expands, breast motion is limited and the breastand its vasculature are compressed. Fluid may also be released from thechamber, and as the chamber deflates, blood flow to the breast isrestored, producing Korotkoff sounds that may be detected by a sounddetection device. Each breast of a patient may separately be subjectedto the foregoing procedure, and data produced from the detected sounds(Korotkoff or otherwise) from one breast may be compared with the dataproduced from the detected sounds from the second (contralateral)breast. The data resulting from such a comparison may be used to enhancevarious diagnostic modalities, including, for example, acomputer-assisted detection process, a mammogram analysis, an evaluationthat utilizes a mammography image database, or another process.

The instant systems include a mammography unit comprising a bucky havingan imaging area; a compression device comprising an x-ray transparentinflatable chamber; a manifold operatively associated with theinflatable chamber for introducing a fluid into the inflatable chamber,for permitting release of fluid from the inflatable chamber, or both;and, a sound detector, wherein when fluid is introduced into theinflatable chamber of the compression device, at least one surface ofthe chamber expands and causes expansion of the compression deviceagainst a breast positioned on the bucky, and also causes at leastpartial occlusion of blood flow to the breast, and wherein when fluid isreleased from the inflatable chamber of the compression device, bloodflow is at least partially restored to the breast and Korotkoff soundsare generated that may be detected by the sound detector.

Methods in accordance with the present invention can comprise securing acompression device comprising an x-ray transparent inflatable chamberover a tube-side surface of a patient's breast positioned on an imagingarea of a bucky on a mammography unit; at least partially filling theinflatable chamber of the compression device with a fluid, therebycompressing the breast between the inflatable chamber and an imagingarea of a bucky and at least partially occluding blood flow to thebreast; transmitting x-rays through the breast and onto the mammogram;releasing at least a portion of the fluid from the inflated at least onechamber, wherein the release of the fluid from the at least one chambercontrols the resumption of blood flow to the breast; and, detectingsounds generated by the resumption of blood flow to the breast.

Also provided are methods comprising securing a first compression devicecomprising an x-ray transparent inflatable chamber over an imaging areaof a bucky of a mammography unit, so that when a patient's breast ispositioned upon the imaging area, the breast is interposed between thefirst compression device and a compression surface positioned above atube-side surface of the breast; at least partially filling theinflatable chamber of the first compression device with a fluid, therebycompressing the breast between the inflatable chamber and thecompression surface and at least partially occluding blood flow to thebreast; transmitting x-rays through the breast; releasing at least aportion of the fluid from the inflatable chamber, wherein the release ofthe fluid from the chamber controls the resumption of blood flow to thebreast; and, detecting sounds generated by the resumption of blood flowto the breast.

Also disclosed are methods comprising securing a first compressiondevice comprising an x-ray transparent inflatable chamber to acompression paddle of a mammography unit having a bucky with an imagingarea; at least partially filling the inflatable chamber of the firstcompression device with a fluid, thereby compressing a patient's breastthat is positioned on the bucky between the inflatable chamber and theimaging area and at least partially occluding blood flow to the breast;transmitting x-rays through the breast; releasing at least a portion ofthe fluid from the inflatable chamber, wherein the release of the fluidfrom the chamber controls the resumption of blood flow to the breast;and, detecting sounds generated by the resumption of blood flow to thebreast.

Also disclosed are methods comprising using a comparison of data derivedfrom the detection of Korotkoff sounds within a patient's first breastand data derived from the detection of Korotkoff sounds within thepatient's contralateral breast to interpret a mammogram.

The present methods also include compressing a breast, whereby theresulting compression occludes at least some blood flow to the breast,at least partially relieving such compression, such that blood flow tothe breast is at least partially restored, and, detecting Korotkoffsounds within the breast.

All of the methods provided herein may be performed with respect to bothbreasts of a patient, preferably via separate but identical repetitionsof the disclosed method steps. Each of the methods may also furthercomprise comparing said detected sounds from said first breast with saiddetected sounds from said contralateral breast. The detected sounds fromthe first breast and the contralateral breast of the patient may each beconverted to an acceptable data format, such as a frequency domainsignal, and the sound data corresponding to the first breast may becompared to the sound data corresponding to the contralateral breast.The comparison may provide a comparision metric, and the resultingmetric may be used in connection with a CAD process, a mammogramanalysis, a comparison with mammography database records, or anycombination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood, and its numerousobjects and advantages will become apparent to those skilled in the artby reference to the following detailed description when taken inconjunction with the following drawings, in which:

FIG. 1 is a schematic oblique view of a section of a traditionalmammography unit.

FIG. 2 is a schematic lateral view of FIG. 1 depicting a breastcompressed with a compression surface.

FIG. 3 is a schematic top view of an embodiment of the tube-sidecompression devices of the present invention.

FIG. 4 is a schematic side view of an embodiment of the tube-sidecompression devices of the present invention.

FIG. 5 is a top view of an embodiment of the tube-side compressiondevices of the present invention.

FIGS. 6A-6C each depict a top view of an embodiment of the bucky-sidecompression devices of the present invention.

FIGS. 7A-7C provide front views of an embodiment of the tube-side,bucky-side, and paddle-mounted compression devices, respectively, of thepresent invention.

FIGS. 8A-8C provide front views of another embodiment of the tube-side,bucky-side, and paddle-mounted compression devices, respectively, of thepresent invention.

FIGS. 9A-9D depict front views of tube-side, bucky-side, both tube-sideand bucky-side, and both bucky-side and paddle-mounted compressiondevices, respectively, of the present invention.

FIG. 10 provides one possible arrangement among components that may beused to detect, store, and process sound information from within apatient's breast.

FIGS. 11A & 11B illustrate prior art and inventive mammographyprocedures, respectively.

FIG. 12 depicts a mammography procedure in accordance with an embodimentof the present invention.

FIG. 13 depicts a mammography procedure in accordance with anotherembodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Provided are mammography systems and methods of using the same, forexample, in association with the process of imaging of a patient'sbreasts.

The instant systems include devices that compress the subject breast (afirst breast or a second, contralateral breast) against a bucky withoutthe need for a traditional mammography unit compression paddle. Thedevices comprise at least one x-ray transparent inflatable chamber forcontaining a fluid, for example, a pressurized gas. Inflatable chamberscan be, for example, medically acceptable balloons. When fluid isintroduced into the chamber, at least one surface of the chamberexpands. The expansion may be in the direction of the bucky, or may bein the opposite direction, depending on the placement of the device, asdescribed herein.

For example, in one embodiment, the devices secure the breast to thebucky by wrapping over the top or “tube-side” surface of the breast (socalled because it is the surface of the breast that is proximal to thex-ray tube of a mammography unit). The compression devices arepreferably adapted for being secured over the tube-side surface of thebreast, i.e., include features that permit the compression device to besecured over the tube-side surface of the breast. For example, sideflaps, cords, straps, or any other suitable feature can be used tosecure the device to and/or around the bucky. Generally, when inposition over the breast (and not inflated), the inflatable chamberpartially conforms to the shape of the breast. Compressed air, forexample, can be introduced, manually or automatically, to inflate thechamber. As the chamber expands, breast motion is limited and the breastis compressed against the surface of the bucky. Inflation of the chambercan at least partially occlude blood flow in the breast.

In another embodiment, the compression devices comprise an x-raytransparent inflatable chamber that is interposed between the breast andthe bucky. These compression devices are referred to as being located“bucky-side”, as they are positioned at the side of the breast that isproximal to the bucky. Such compression devices are preferably adaptedto secure the device on top of the bucky, i.e., include features thatpermit the compression device to be secured over the tube-side surfaceof the breast. For example, side flaps, cords, straps, or any othersuitable feature can be used to secure the device to and/or around thebucky. Fluid can be introduced to inflate the chamber, and when a paddleor an inflatable chamber device in accordance with the precedingembodiment (i.e., a device that is wrapped over the tube-side surface ofthe breast) is positioned over the breast, the inflation of the chambercan compress the breast against the paddle or tube-side device. Here,too, inflation of the chamber can at least partially occlude blood flowin the breast.

Traditional mammography units employ a compression paddle, whichincludes a rectangular flat plate that is attached to the mammographyunit between an x-ray tube assembly and the bucky. The compressiondevices of the instant invention can comprise an x-ray transparentinflatable chamber that is secured to the underside of the paddle, i.e.,the side of the flat paddle that is proximal to the bucky. Suchcompression devices are herein referred to as “paddle-mounted” devices.For example, side flaps, cords, straps, or any other suitable featurecan be used to secure the device to and/or around the paddle. Generally,when in position over the breast (and not inflated), the inflatablechamber partially conforms to the shape of the breast. Compressed air,for example, can be introduced, manually or automatically, to inflatethe chamber. As the chamber expands, breast motion is limited and thebreast is compressed against the surface of the bucky. Inflation of thechamber can at least partially occlude blood flow in the breast.

The inventive system may therefore include a tube-side compressiondevice, a bucky-side compression device, a paddle-mounted compressiondevice, or may comprise a bucky-side device with a paddle-mounteddevice, or a bucky-side device with a tube-side device.

In each of these embodiments, fluid may be released from the chamber(s)via a valve or some other outlet means, and as the chamber(s) is atleast partially deflated, blood flow is restored to the breast,producing Korotkoff sounds that may be detected by a sound detectiondevice.

In 1905, Dr. Nikolai Korotkoff reported that turbulence in blood flow invivo can produce audible sounds. These sounds are now routinely used tomeasure blood pressure, typically through use of a stethoscope inconjunction with a blood pressure gauge (sphygmomanometer). However, thedetection of Korotkoff sounds has never been used or proposed for use inconnection with the mammography process. The instant invention involvesthe use of Korotkoff sounds during mammography to generate useful dataconcerning the vascularity of the subject breast. Angiogenesis plays animportant role in the development of breast carcinoma, and informationconcerning the vascularity of a patient's breast can improve thediagnostic process. Furthermore, Korotkoff sounds can provideinformation about breast vascularity in regions highlighted bycomputer-assisted detection (CAD) methods. This information could beuseful in differentiating between benign and malignant breast conditionsprior to biopsy. Currently, it is known that the increased rate ofbiopsy that has resulted from the use of CAD is not clearly associatedwith improved detection of invasive breast cancer (Fenton J J et al.,2007), and the introduction of a new data parameter to enhance the CADprocess could reduce the incidence of unnecessary biopsies.

In addition, in view of the fact that a standard breast checkup mayinclude the examination of both breasts of a patient, the instantinvention may involve the detection of Korotkoff sounds from both afirst breast of a patient and the contralateral breast of a patient.Sound data from both breasts may be used to enhance the diagnosticprocess, for example, by permitting a comparison between the data from afirst breast to the data from the contralateral breast; it is frequentlythe case that a breast condition is present in only one of a patient'sbreasts, and a difference between the data obtained from a patient'srespective breasts can alert a practitioner to the possibility that oneof the breasts should be subjected to further examination. The dataobtained from a patient's respective breasts may also or alternativelybe used, for example, to enhance a computer-assisted detection (CAD)program, to aid in the analysis of a mammogram, in conjunction with theuse of a database of mammography images, or any combination thereof.

For example, if an area of interest is identified in a first breast by aCAD program (e.g., by the identification of a location in the image of abreast having a certain pixel value, corresponding to a higher thanaverage optical density), sound data from the area of interest in thefirst breast may be obtained and compared with sound data from thecorresponding anatomical area of interest in the second breast; if thecomparison indicates a significant difference between the acousticproperties in the area of interest in the first breast and the acousticproperties in the corresponding area in the second breast, such findingsmay buttress the findings of the CAD program, and thereby alert thepractitioner and/or warrant additional studies. Alternatively, if thedifference between the sound data from the first breast and the sounddata from the contralateral breast is within a certain range oftolerance, then the practitioner could have reason to suspect that thearea of interest as designated by the CAD program is not the site of amalignant growth. It is well known that the blood flow properties,caused, for example, by differences in blood vessel diameter and growthdensity, are different in cancerous tissue than in normal tissue. Unlikeprior methods, the present invention exploits the sounds created by theblood flow properties of a tissue (such as a site of interest) within abreast or the global blood flow properties of a breast, as well as acomparison with corresponding properties in a contralateral breast, inorder to obtain valuable additional data parameters regarding thephysiological characteristics of a patient's breasts.

The comparison of sound data obtained from a patient's respectivebreasts can also be used to generate a data metric that can be used toenhance the evaluation of a CAD-generated tissue analysis, of amammogram, of a set of data obtained from a mammography database, or anycombination thereof. As used herein, the “metric” is simply a dataparameter that results from the comparison of data obtained through thedetection of sounds from a first breast of a patient with data obtainedthrough the detection of sounds from a second, contralateral breast ofthe patient. The metric may be a sound frequency ratio that can becompared to a ratio that was obtained from a pair of breasts in which acancerous growth was known to be absent, to a ratio that was obtainedfrom a pair of breasts in one of which breasts a cancerous growth wasknown to be present, or both. For example, if the metric consists of aratio, it may be known to the practitioner that ratios that are between1.5:1 and 1:1.5 represent breasts in which there are not significanttissue differences (which would otherwise indicate tissue properties inone breast that are not present in the other breast). On the other hand,if the ratio is found to be outside of a known range of tolerance, sucha finding may be indicative of a clinically significant difference inthe blood flow characteristics (and therefore the tissue properties)between a first breast and the contralateral breast. In anotherembodiment, the metric may be an amplitude ratio, a time ratio, or acombination of any of the preceding.

Thus, in the present invention, the inflatable chamber can effectivelyfunction in the manner of a blood pressure cuff, and the sound detectorcan be used to ascertain Korotkoff sounds, which can in turn be used,alone or in connection with the CAD process, to enhance and improve theprocess of assessing the condition of the subject breast. For example,the current invention can be used to identify blood flow sounds in abreast at regions of interest as identified by CAD methods, therebyproviding an additional parameter to the process of assessing a breastfor the presence or absence of cancerous growth. A comparison betweenthe Korotkoff sounds obtained from a first breast and those obtainedfrom a contralateral breast yields additional data that can also beapplied to the evaluation of a CAD image, a mammogram, and/or acomparison to database records.

Additionally, because the inflatable chamber can be used to gate bloodflow to the breast during the mammography process, unlike traditionaldevices and methods, the present invention is compatible with contrastand molecular imaging studies that rely on the access of imaging agentsto breast vascularity. For example, x-ray absorbing contrast material issystemically administered to a patient via injection. Under this mannerof administration, if it is desired to utilize the contrast material byx-ray imaging of the breast, it is difficult to ascertain the precisetime at which the contrast material enters the breast in order tocapture an x-ray image of the breast at the moment of such entry.Because the instant inflatable chamber can be used to gate blood flowinto a compressed breast, i.e., determine the precise time at whichblood from the body is permitted to reenter the breast followingcompression, the present invention permits a clinician to time thecapture of an x-ray image of the breast just as blood containing acontrast material resumes its flow into that breast. The x-ray imagefeaturing the contrast material as distributed within the breast can beused to improve the diagnosis of the subject, for example, by aiding inthe interpretation of CAD-generated data.

There are also provided mammography units comprising a bucky having animaging area; a compression device comprising an x-ray transparentinflatable chamber and a manifold operatively associated with theinflatable chamber for introducing a fluid into the inflatable chamberand/or for receiving the fluid from the inflatable chamber; and, a sounddetector capable of detecting Korotkoff sounds, wherein when fluid isintroduced into the chamber of the compression device, at least onesurface of the chamber expands and causes expansion of the compressiondevice against a breast positioned on the bucky and causes at leastpartial occlusion of blood flow to the breast, and wherein when fluid isreleased from the inflatable chamber of the compression device, bloodflow is at least partially restored to the breast and Korotkoff soundsare generated that may be detected by the sound detector. In oneembodiment, a source of compressed air that is in fluid communicationwith the manifold is provided.

Inflatable chambers increase in volume when pressurized fluid isintroduced. A medically acceptable balloon is an example of aninflatable chamber. Chambers used in embodiments of the presentinvention can be, for example, high pressure balloons. High pressureballoons are used in various applications in the medical industry, suchas in angioplasty. See Saab, Applications of High-Pressure Balloons inthe Medical Device Industry,http://www.advpoly.com/NewsData/BalloonPaper.pdf.(http://www.devicelink.com/mddi/archive/00/09/003.html)

In some embodiments, the device comprises multiple inflatable chambers.For example, a second inflatable chamber can be used to help distributethe compression force exerted against the breast. The shape of thechambers can vary as needed. In the present disclosure, recitation of“an x-ray transparent inflatable chamber” can mean “at least one x-raytransparent inflatable chamber.” More generally, in the presentdisclosure the singular forms “a,” “an,” and “the” include the pluralreference, and reference to a particular numerical value includes atleast that particular value, unless the context clearly indicatesotherwise. Thus, for example, a reference to “a sound detector” is areference to one or more of such sound detectors and equivalents thereofknown to those skilled in the art, and so forth. For purposes of thepresent disclosure, all references to devices or methods in which “abreast” or “the breast” is analyzed are intended to embrace the analysisof one breast of a patient or both breasts of the patient. For example,it is intended that any method that is described with respect to abreast of a patient is applicable to the other breast of a patient, andany method steps recited therein with respect to one breast may berepeated in connection with the second breast of the patient.Furthermore, it is preferred that such method steps are performedseparately with respect to each breast; for example, the step of“detecting sounds within the first breast and within the contralateralbreast when such breasts are not compressed” means that the detection ofsounds within the first breast is performed in an episode that isseparate but identical to the detection of sounds within thecontralateral breast.

In some embodiments, there is an x-ray transparent cover thatsubstantially surrounds the inflatable chamber. The x-ray transparentcover can be compressible. The x-ray transparent cover can also oralternatively be disposable. For example, in one embodiment, a cuff madeof compressible material can have a pocket for holding a high pressureballoon where the cuff wraps around the breast and the bucky. In anotherembodiment, to avoid direct contact with the patient's skin, adisposable x-ray transparent thin plastic sheet can be used between thetube-side surface of the breast and the inflatable chamber.

Any portion of the instant devices can comprise radiopaque indicia. Forexample, the indicia can impart information onto the mammogram in anarea away from the breast.

Regarding indicia, it may be desirable to provide information including,but not limited to, the physical properties of the compression device,such as density or thickness, the location of the device, themanufacturer of the device, and/or the date of manufacture. In addition,it may be useful for compression devices to have unique serial numbers,that may, for example, aid in tracking re-use of the devices. Inaccordance with the present invention, information can be provided onthe mammogram in an area away from an image of the breast.

Reference herein to “cassette holder” and “bucky” means the device thatholds an image receptor for the creation of a mammogram, regardless ofwhether the image receptor is film-based or digital.

An identifier is radiopaque such that identifying indicia can be eitherx-ray transparent or radiopaque, and the remaining portion of theidentifier would be radiopaque or x-ray transparent, respectively. Byreference to the radiopaque nature of an identifier, it is understoodthat the identifier may not be completely radiopaque, but itsradiopacity would be sufficiently different from the radiopacity of thesurrounding materials, e.g., x-ray transparent compressible materials orx-ray transparent covers, so as to be recordable, e.g.,radiographically, on a mammogram. The identifier can comprise a varietyof radiopaque materials, e.g., paper, plastic, or metal. In such anembodiment, identifying indicia would be x-ray transparent. If desired,in another embodiment, identifying indicia can be imprinted withradiopaque ink onto x-ray transparent compressible material or x-raytransparent covers.

As used herein, the “sound detector” is any device that is capable ofdetecting those sounds that are produced by the flow of blood withintissue, such as a subject breast. For example, any device that functionscomparably with a stethoscope may be used. Electronic sound detectorsinclude sensors that may be taped to the outer surface of patient skinat particular locations or that may be affixed proximate to theinflatable chamber of a compression device. When affixed proximate tothe inflatable chamber of a compression device, the sound detectors areideally placed in fluid communication with such inflatable chamber, sothat Korotkoff sounds can travel from their locus of origin within thebreast to the sound detector via the inflatable chamber, and suchconfiguration works best when the inflatable chamber is at leastpartially filled with fluid. Preferably, the sound detector is adaptedto generate an electrical signal that can be converted to a frequencydomain signal that can in turn be digitized for computer storage. Morepreferably, the sound detector is adapted to permit transfer of thedetected sound information to a separate device that can convert thedetected sound information to a frequency domain signal that can bedigitized for computer storage. Frequency domain signal conversion anddigitization are processes that are widely understood by those skilledin the art, and the skilled artisan will readily appreciate how a sounddetector may be adapted for use with such processes.

As sound detectors will typically be only partially x-ray transparent(if at all), the sound detectors are ideally a) positioned outside ofthe x-ray field; b) controlled manually or automatically to enter thex-ray field of the mammography unit at preselected times, i.e., whenx-ray images are not being captured; or, c) easily movable from withinthe x-ray field to outside of the x-ray field.

Preferably, the sound detectors can be activated at any time during themammography process. For example, sound detectors can be used to detectsounds from within a breast prior to compression by an inflatablechamber, during compression by an inflatable chamber, as compression byan inflatable chamber is being relieved by partial deflation of theinflatable chamber, and/or after compression of the breast has beenfully relieved. Episodes of sound detection may be performed at any timein relation to the capture of x-ray images.

Sounds that are ascertained by the sound detector and converted torecordable data can subsequently be compared with libraries of soundsfrom known cases of cancer, for example, to determine the probability ofmalignancy. A clinician can also correlate Korotkoff sound data with theinformation regarding visual mammography features stored in the DigitalDatabase for Screening Mammography (“DDSM”). The DDSM is a publiclyavailable library of features observed on mammograms that can be used asa reference during the diagnostic process. See Heath M et al., “TheDigital Database for Screening Mammography”, in The Proceedings of the5th Int'l Workshop on Digital Mammography (Toronto, Canada, June 2000),Medical Physics Publishing (Madison, Wis.). As used herein, a“mammography database” may include databases of mammography images,whether such images are digitized or analog.

The CAD process as used in connection with mammogram analysis hasrecently been criticized as being responsible for the generation offalse positives and the performance of unnecessary biopsies (Fenton J Jet al., 2007). The data acquired through use of the sound detector canbe integrated into a CAD algorithm, thereby providing a refinement ofthe CAD process by introducing an additional data parameter (i.e.,Korotkoff sound).

The preceding is also true with respect to a comparison of the sounddata that are ascertained from a first breast of a patient with thesound data that are ascertained from the contralateral breast of apatient. The comparison of the sound data from the respective breasts ofa patient can be used to generate a metric, for example, a ratio, thatcan be evaluated in the light of comparable data from subjects in whichan abnormal condition was known to be absent, known to be present, orboth. In other words, comparison of a such a metric with informationfrom a database can provide the diagnostician with informationpertaining to the condition of one or both of the patient's breasts.

Methods in accordance with the present invention can comprise securing acompression device comprising an x-ray transparent inflatable chamberover a tube-side surface of a patient's breast positioned on an imagingarea of a bucky on a mammography unit; at least partially filling theinflatable chamber of the compression device with a fluid, therebycompressing the breast between the inflatable chamber and the imagingarea and at least partially occluding blood flow to the breast;transmitting x-rays through the breast; releasing at least a portion ofthe fluid from the inflatable chamber, wherein the release of the fluidfrom the chamber controls the resumption of blood flow to the breast;and, detecting sounds generated by the resumption of blood flow to thebreast. The instant methods may be performed with respect to bothbreasts of a patient, preferably via separate but identical repetitionsof the disclosed method steps. The methods may also further comprisecomparing said detected sounds from said first breast with said detectedsounds from said contralateral breast. The detected sounds from thefirst breast and the contralateral breast of the patient may each beconverted to an acceptable data format, such as a frequency domainsignal, and the sound data corresponding to the first breast may becompared to the sound data corresponding to the contralateral breast.The comparison may provide a comparision metric, and the resultingmetric may be used in connection with a CAD process, a mammogramanalysis, a comparison with mammography database records, or anycombination thereof.

Also provided are methods comprising securing a first compression devicecomprising an x-ray transparent inflatable chamber over an imaging areaof a bucky, so that when a patient's breast is positioned upon theimaging area, the breast is interposed between the first compressiondevice and a compression surface positioned above a tube-side surface ofthe breast; at least partially filling the inflatable chamber of thefirst compression device with a fluid, thereby compressing the breastbetween the inflatable chamber and the compression surface and at leastpartially occluding blood flow to the breast; transmitting x-raysthrough the breast; releasing at least a portion of the fluid from theinflatable chamber, wherein the release of the fluid from the chambercontrols the resumption of blood flow to the breast; and, detectingsounds generated by the resumption of blood flow to the breast. Theinstant methods may be performed with respect to both breasts of apatient, preferably via separate but identical repetitions of thedisclosed method steps. The methods may also further comprise comparingsaid detected sounds from said first breast with said detected soundsfrom said contralateral breast. The detected sounds from the firstbreast and the contralateral breast of the patient may each be convertedto an acceptable data format, such as a frequency domain signal, and thesound data corresponding to the first breast may be compared to thesound data corresponding to the contralateral breast. The comparison mayprovide a comparision metric, and the resulting metric may be used inconnection with a CAD process, a mammogram analysis, a comparison withmammography database records, or any combination thereof.

The compression surface can be a traditional paddle or can be atube-side compression device as described previously. When thecompression surface is a paddle, a paddle-mounted compression devicecomprising an x-ray transparent inflatable chamber can be securedthereto; the paddle-mounted compression device can also be at leastpartially filled with a fluid and used to compress the breast betweenitself and the bucky-side compression device.

The inventive methods can include the use of both a compression devicethat is secured over the tube-side surface of a breast and a compressiondevice that is secured to the mammography unit between the breast andthe bucky, or both a compression device that is paddle-mounted and acompression device that is secured to the mammography unit between thebreast and the bucky, inflating one or more chambers of either or bothof the compression devices; compressing a breast; transmitting x-raysthrough the breast, releasing at least a portion of the fluid from theinflated chambers of the compression devices, and detecting soundsgenerated by the resumption of blood flow into the breast.

Also disclosed are methods comprising securing a first compressiondevice comprising an x-ray transparent inflatable chamber to acompression paddle of a mammography unit having a bucky with an imagingarea; at least partially filling the inflatable chamber of the firstcompression device with a fluid, thereby compressing a patient's breastthat is positioned on the bucky between the inflatable chamber and theimaging area, and at least partially occluding blood flow to the breast;transmitting x-rays through the breast; releasing at least a portion ofthe fluid from the inflatable chamber, wherein the release of the fluidfrom the chamber controls the resumption of blood flow to the breast;and, detecting sounds generated by the resumption of blood flow to thebreast. The instant methods may be performed with respect to bothbreasts of a patient, preferably via separate but identical repetitionsof the disclosed method steps. The methods may also further comprisecomparing said detected sounds from said first breast with said detectedsounds from said contralateral breast. The detected sounds from thefirst breast and the contralateral breast of the patient may each beconverted to an acceptable data format, such as a frequency domainsignal, and the sound data corresponding to the first breast may becompared to the sound data corresponding to the contralateral breast.The comparison may provide a comparision metric, and the resultingmetric may be used in connection with a CAD process, a mammogramanalysis, a comparison with mammography database records, or anycombination thereof.

The instant methods can further comprise using a source of compressedair to inflate the chamber of the compression device.

With respect to the present methods, the detection of sounds may beperformed prior to compression of a patient's breast, during compressionof a patient's breast, or following compression of a patient's breast.The detection of sounds within the breast may also be conducted at anystage of compression of the breast, i.e., when the breast is onlypartially compressed, or when the breast of fully compressed. When thesound detection step occurs at a specific stage during the instantmethods with respect to a first breast, a sound detection step shouldalso be performed at the same stage in the contralateral breast so thatappropriate data comparisons may be made. When the methods involve theuse of a compression device having an inflatable chamber, the detectionof sounds within the breast may occur prior to at least partiallyfilling the chamber of the compression device, when the chamber of thecompression device has been at least partially filled, when the fluidintroduced into the chamber of the compression device has been at leastpartially released from the chamber, when the fluid has been releasedfrom the chamber to the extent necessary to allow blood flow to thebreast to be at least partially restored, or when the fluid has beenreleased from the chamber to the extent necessary to allow blood flow tothe breast to be substantially completely restored. One or more x-rayimages of the breast may be acquired at any stage during the performanceof the instant methods in relation to the detection of sound or thecompression of the patient's breast.

The detection of sounds generated by the resumption of blood flow to thebreast may be conducted locally (i.e., at a portion or portions of thebreast), or may be conducted over the entire breast (“globally”). Ifsound is detected locally, the portion(s) of the breast at which soundis detected may be a site of interest. A site of interest may bedetermined through reference to an image of the breast that was acquiredprior to the sound-detection stage. For example, sound may be detectedlocally at a site of interest as identified through CAD methods. Onceidentified, the sound data retrieved from a site of interest within onebreast may be compared with sound data that is retrieved from thecorresponding anatomical location on the contralateral breast. Thecomparison can yield information regarding whether the site of interestis physiologically distinguishable from comparable tissue that isotherwise believed to be normal. Such findings may buttress the findingsof the CAD program, and thereby alert the practitioner and/or warrantadditional studies; alternatively, if the difference between the sounddata from the first breast and the sound data from the contralateralbreast is within a certain range of tolerance, then the practitionercould have reason to suspect that the area of interest as designated bythe CAD program is not the site of a malignant growth.

In another embodiment, the methods can additionally comprise convertingthe detected sounds to an acceptable data format, such as a frequencydomain signal. The converted sounds can be digitized for computerstorage. The converted sounds can also be compared to sounds detectedfrom other tissue samples. The tissue samples can be from a breast,including from a contralateral breast of the same patient, and thebreast can be one in which cancerous growth is known to be absent, orcan be one in which cancerous growth is known to be present.

The inventive methods can further comprise introducing a detectibleagent into the subject to which the breast belongs, or directly into thebreast. The detectible agent may be a molecular agent, or a contrastagent, or both a molecular agent and a contrast agent may be introducedinto the subject/breast. In most instances, when a detectible agent isintroduced into one breast of a patient, normal blood flow will causethe detectible agent to enter the contralateral breast; however, ifsufficiently small quantities of a detectible agent are used, it may benecessary to introduce the detectible agent into both of the patient'sbreasts. In another embodiment, the methods can comprise introducing adetectible agent into the subject or subject's breast, releasing atleast a portion of the fluid from the inflated chambers of thecompression devices, and imaging the breast. Exemplary molecular agentsinclude radioactive agents. The contrast material is preferably an x-rayabsorbing substance, such as an iodide compound, but may be anothermaterial. Thus the inventive methods can include introducing an iodidecompound into the subject/breast, releasing at least a portion of thefluid from the inflated chambers of the compression devices, and imagingthe breast, i.e., just as the iodide compound enters the breast via theresumption of blood flow. Unlike existing mammography devices andmethods, the present invention is compatible both with traditionalmammography procedures (e.g., x-ray imaging) and with procedures thatrequire the at least partial resumption of blood flow within the breast,such as Korotkoff sound detection (as herein described), and techniquesthat involve the deployment of detectible agents such as molecular orcontrast agents within the breast vascularity.

Also provided are methods comprising using data derived from thedetection of Korotkoff sounds within a breast to interpret a mammogram.In accordance with the present invention, data that are derived from thedetection of Korotkoff sounds within a patient's first breast arecompared with data derived from the detection of Korotkoff sounds withinthe patient's contralateral breast in order to interpret a mammogram. Insome instances, the data may be used to designate one or more regions ofinterest on a mammogram. The sound data may be used by a radiologist tointerpret a mammogram (including to designate one or more regions ofinterest on a mammogram), or may be used during a computer-assisteddetection (CAD) process in order to interpret a mammogram such as byflagging regions of interest for review by a radiologist, or both. Ineither of the latter two instances, the CAD process may make use of analgorithm that is specially adapted for integrating sound data into theinterpretation and/or flagging process. In a typical examination, aradiologist will compare the image obtained from one breast to the imageobtained from the contralateral breast of the patient to identifyregions of interest. Likewise, the sound pattern from a breast having amalignancy can be expected to be distinguishable from the sound patternfrom contralateral breast without a malignant growth.

Also disclosed are methods comprising compressing a breast, whereby theresulting compression occludes at least some blood flow the breast; atleast partially relieving the compression, such that blood flow to thebreast is at least partially restored, and detecting Korotkoff soundswithin the breast. As previously indicated, the instant methods may beperformed with respect to both breasts of a patient, preferably viaseparate but identical repetitions of the disclosed method steps. Thesound detection step may occur at any stage during the instant methods,but it is preferred that at least one instance of sound detection beperformed following the compression stage when blood flow to the breasthas at least partially resumed. In addition, when the sound detectionstep occurs at a specific stage during the instant methods with respectto a first breast, a sound detection step should also be performed atthe same stage in the contralateral breast so that appropriate datacomparisons may be made. Once sounds have been detected the sound datamay be converted to a frequency domain signal or other acceptable dataformat, such conversion being readily understood by those skilled in theart. In accordance with the present invention, sound data that isobtained from the first of a patient's breasts may be compared with thesound data that is obtained from the patient's contralateral breast. Thedata comparison may be used to yield a comparison metric, which may, forexample, take the form of a ratio. The metric may be used during theanalysis of at least one of a computer-assisted detection process, amammogram, or a database of mammography images. The sound data maybeused to designate regions of interest within a breast, for example, inany manner as described previously, such as by a radiologist, or duringthe process of computer-assisted detection (CAD) or both. The instantmethods may additionally comprise transmitting x-rays through the breastin order to obtain a mammogram. One or more x-ray images of the breastmay be acquired at any stage during the performance of the instantmethods in relation to the detection of sound or the compression of thepatient's breast.

Referring now to the drawings wherein reference numerals refer to likeelements, FIGS. 1 and 2 depict two views of a mammography unit inaccordance with an embodiment of the present invention having an x-raytube 1 that produces an x-ray beam (not numbered) connected to a cone 2that houses a collimator 7. The collimator 7 restricts the size andshape of the x-ray beam in any plane perpendicular to the axis of thex-ray beam. The x-ray beam also passes through a compression surface 3,which may be a paddle or a compression device according to the presentinvention. A cassette holder 4, comprises a tube-side surface containingan imaging area 11 and a solid area 8; an outer surface 10 that is inclose proximity or in contact with a patient's chest wall duringexamination; and a cassette tunnel opening 6. Generally, in a film-basedcassette holder, a cassette tunnel located below the imaging area housesan antiscatter grid and a cassette. The cassette holder 4 is held inplace by a support member 5 and slidably engages with a support column(not numbered). The x-ray beam passes through imaging area 11 to exposea film in the cassette. In a digital unit, the cassette tunnel openingsare not present. X-ray beams used in conjunction with a digital buckyare received electronically. The solid area 8 is typically nottransparent to x-ray beams and secures the cassette holder or bucky tothe support column. A patient's breast (not numbered) is positioned onthe imaging area 11 of the tube-side surface of the cassette holder 4and is compressed by the compression surface 3.

FIG. 3 is a schematic top view of an embodiment of the presentinvention. FIG. 4 is a schematic side-view of an embodiment of thepresent invention. An x-ray transparent inflatable chamber 112 has atleast one manifold 114 that is operatively associated with the chamber112, which can introduce compressed gas, for example, into the chamberand/or receive compressed gas to vent it from the chamber. A source offluid, for example, compressed air, enters the chamber 112 of the device100 through a manifold 114. An optional second manifold 116 can beoperatively with the chamber for venting or fluid inlet purposes. Thedevice 100 may be used in securing a patient's breast to a bucky bywrapping over the breast. The device 100 can alternatively be mountedonto a paddle, for example, by wrapping over the underside of thepaddle. In an embodiment, one or more flaps, 118 and 120, made of, forexample, adhesive or elastic, attach to one or more ends of the chamber.When device 100 is used in securing a patient's breast to a bucky bywrapping over the breast, the flaps optionally have one or more openings122, 124 to permit a film cassette to pass through them into thecassette holder.

In some embodiments, an x-ray transparent cover 126 substantiallysurrounds the inflatable chamber. In some instances, it may be desirablethat the x-ray transparent cover is compressible. In other instances,the x-ray transparent cover is disposable. A combination of compressibleand disposable covers can also be used. For example, in one embodiment,a cuff made of compressible material can have a pocket for holding ahigh pressure balloon where the cuff wraps around and/or releasablyadheres to the breast and the bucky.

In one embodiment, the inflatable chamber has multiple chambers. In oneexample, a chamber is nested within the cavity of another chamber.Another example is a combination of chambers next to each other. The useof multiple chambers can be used to help distribute the compressionforce exerted against the breast. The shape of the chambers can vary asneeded too.

In evaluating equivocal areas of a mammogram it is sometimes desirableto provide a greater degree of compression in a localized area of abreast than can be achieved by uniform compression. This procedure,called spot compression, can be accomplished with the present inventionby configuring at least one surface of the chamber with an area thatexpands to a greater degree than the surrounding surface, andpositioning this area over the region of interest. Alternatively, anx-ray transparent semi-rigid plastic disc can be placed on the breastover the area of interest before overlaying the breast with thecompression device. As air is introduced into the chamber, the disc ispushed against the breast to exert additional compression force in thelocalized area. The discs can vary in size as needed. Identical episodesof spot compression may be separately performed with respect to each ofa patient's breasts. Preferably, if a certain variation on compressionis performed with respect to a first of a patient's breasts, then thesame type of compression should be performed for purposes of theanalysis of the second of the patient's breasts.

Any portion of the devices can comprise radiopaque indicia. FIG. 5 is atop-view of a device 100 that wraps over the tube-side area of a breastand contacts the surface of the bucky. Optionally, indicia 128 iscontained on a surface of the device 100. Preferably, the indiciaimparts information onto the mammogram in an area away from the breast.

FIG. 6A is a top view of a compression device 217 in accordance with theinvention that can be positioned over the bucky 4 and imaging area 11,i.e., beneath the breast when the breast is in position on mammographyunit (hereinafter referred to as a “bucky-side compression device”).Bucky-side compression device 217 is depicted with optional openings212, 214, flattened, to show sections 210, 211, 213, and 215 forcovering patient-contact surfaces of a cassette holder. In one example,a compression device 217 is at least partly fabricated with acompressible material. Compressible material is preferably low Z elasticmatrix material. An identifier 290 is partially radiopaque such thatinformation about the material can be imparted onto a mammogram.

Bucky-side compression device 217 is equipped with one or more x-raytransparent inflatable chambers 218 having at least one manifold (notshown) that is operatively associated with each inflatable chamber,which can introduce compressed gas, for example, into the chamber 218and/or receive compressed gas to vent it from the chamber 218. A sourceof fluid, for example, compressed air, enters one or more chambers 218of the bucky-side compression device 217 through a manifold (not shown).An optional second manifold can be operatively with the chamber 218 forventing or fluid inlet purposes.

In another example, as shown in FIG. 6B, the compression device of FIG.6A is depicted with optional section 216 which is an extension of thecompressible material that can be adapted with methods for retaining thecompressible material in place on the cassette holder. Furthermore,there is no limitation on the material used to fabricate section 216.Although x-ray transparent compressible material may be used tofacilitate ease of manufacture of the bucky-side compression device, itis understood that oftentimes section 216 need not be x-ray transparent,because x-ray beams do not need to penetrate that area, norcompressible, because a patient typically does not contact that area.Optional section 216 can be integral with the bucky-side compressiondevice 217 or attached separately.

In yet a further example, as shown in FIG. 6C, the bucky-sidecompression device of FIG. 6A is depicted with optional fasteners 240and 242 which secure the device by wrapping around the underside of thesupport member 5. One fastener is shown on each opposite side of thebucky-side compression device, however, it is contemplated that multiplefasteners are suitable for attaching along either side. Furthermore, onefastener can be used which secures to an opposite side of the bucky-sidecompression device. In another embodiment, the compression devicedepicted in FIG. 6C can be paddle-mounted. In this embodiment, onlysection 210 is preferably present, and the attached ends of fasteners240, 242 can be affixed to section 210 of the device, the loose endsbeing used to secure the paddle-mounted device to the paddle.

Fasteners can be straps that meet underneath the support member or abovethe paddle and tie together. In another example, fasteners can engagewith each other using hook and loop fasteners. Yet another embodimentincludes fasteners that can be one-piece elastic bands which are fixedto opposite sides of the compression device. The fasteners can befabricated of any material suitable for fastening and unfastening. Forease of manufacture, however, it may be desirable to fabricate thefasteners out of the compressible material of the bucky-side compressiondevice. Fasteners can be integral with the bucky-side compression deviceor paddle, or may be attached separately.

In FIG. 7A, depicting a side view of an embodiment of the presentinvention, a compression device is positioned over a patient's breast incontact with the tube-side surface of the breast, referred to as suchbecause this is the surface facing an x-ray tube of the mammographyunit. In this embodiment, there are two side flaps 118 and 120 thatsecure the breast to the bucky 4 and attach to support member 5 (when afilm-based bucky is being used). As shown in FIG. 8A, a free end of afirst flap 130 can have a first fastener, 132. A second free end 138 canhave a second fastener 140. The fasteners are optionally attachable orengagable with each other or individually to the bottom of the supportmember or bucky. In another example, a flap is secured, eitherpermanently or removable, to a surface of the bucky. Generally, when inposition over the breast (and not inflated) as shown in FIG. 7, the oneor more inflatable chambers 112 partially conform to the shape of thebreast. Compressed air, for example, can be introduced, manually orautomatically, to inflate the chamber 112.

FIG. 7B provides a side view of another embodiment of the presentinvention in which a bucky-side compression device 217 is positionedbetween a patient's breast and the bucky 4, in contact with thebucky-side portion of the breast. There may be two side flaps 211 and215 that secure the breast to the bucky 4, and may attach to supportmember 5 (when a film-based bucky is being used). As shown in FIG. 8B, afree end of a first flap 211 can have a first fastener, 240. A free endof second flap 215 can have a second fastener 242. The fasteners areoptionally attachable or engagable with each other or individually tothe bottom of the support member or bucky. Generally, when in positionbeneath the breast (and not inflated) as shown in FIGS. 7B & 8B, theinflatable chamber(s) 218 (internal—not shown) of the bucky-sidecompression device 217 partially conforms to the shape of the breast.Compressed air, for example, can be introduced, manually orautomatically, to inflate the chamber 218.

FIG. 7C provides a side view of yet another embodiment of the presentinvention in which a paddle-mounted compression device 219 is provided.There may be two side flaps 221 and 223 that secure the breast to thepaddle 3. As shown in FIG. 8C, a free end of a first flap 221 can have afirst fastener, 225. A free end of second flap 223 can have a secondfastener 227. The fasteners are optionally attachable or engagable witheach other or individually to the bottom of the support member or bucky.Generally, when in position on the underside of the paddle (and notinflated) as shown in FIGS. 7C & 8C, the inflatable chamber(s)(internal—not shown) of the paddle-mounted compression device 219partially conforms to the shape of the breast. Compressed air, forexample, can be introduced, manually or automatically, to inflate thechamber.

As illustrated in FIG. 9A, when fluid is introduced into a chamber 112of the tube-side compression device, at least one surface of the chamberexpands in the direction of the bucky 4. As the chamber expands, breastmotion is limited and the breast is compressed against the bucky 4.Likewise, as depicted in FIG. 9B, when fluid is introduced into achamber 218 of a bucky-side compression device, at least one surface ofthe chamber expands in the direction of the compression surface 3 (whichmay be a paddle or a tube-side compression device according to thepresent invention), and as the chamber 218 expands, the breast iscompressed against the compression surface 3. FIG. 9C provides anembodiment of the current invention in which both a tube-side and abucky-side compression device are present, and wherein fluid has beenintroduced into chamber 112 of the tube-side device and into chamber 218of the bucky-side device. The breast is compressed between the tube-sideand bucky-side devices by the expansion of chambers 112 and 218. FIG. 9Dprovides an embodiment of the current invention in which both apaddle-mounted and a bucky-side compression device are present, andwherein fluid has been introduced into the inflatable chamber (112 or218) of the paddle-mounted device and into the inflatable chamber 218 ofthe bucky-side device. The breast is compressed between thepaddle-mounted and bucky-side devices by the expansion of the chambersof the respective devices.

FIG. 10 depicts one possible arrangement among components that may beused to detect, store, and process sound information from within apatient's breast. A sound detector 250 is preferably placed in fluidcommunication with a breast, so that sounds may be faithfullytransmitted therebetween. For example, the sound detector 250 may beaffixed to the outer surface of the breast, or may be contacted with theinflatable chamber of a compression device in accordance with presentinvention. The sound information received by the detector 250 istransmitted to signal processor 260, which performs a conversion of theacoustical information received by the sound detector 250 into afrequency domain signal that is suitable for transfer by a computer 270.Computer 270 includes software for analyzing the data obtained from thesignal processor 260. For example, the analysis software may include analgorithm that incorporates the sound data into a CAD program that usesthe sound data and x-ray data to mark sites of interest on a mammogram.A recording device 280 stores the output of the computer softwareanalysis and makes it available for retrieval, for example, by aradiologist or other clinician.

FIGS. 11A & 11B illustrate prior art and inventive mammographyprocedures, respectively. Referring to FIG. 11A, in accordance withtraditional procedures, the patient's breast is positioned on amammography unit, and a mammogram is conducted 300 to acquire an imageof the breast. Next, at step 310, the mammogram image is generated andthe attending radiologist will analyze the optical density patternspresent on the image in order to identify regions of interest that mayindicate the presence of cancerous growth. The radiologist may alsoconduct an analysis of a CAD-generated image corresponding to themammogram acquired in step 300. If the radiologist concludes that thevisual region of interest represents normal tissue at step 320, nofurther action is taken. However, if the radiologist believes that thevisual region of interest could represent cancerous growth at step 322,a recommendation will be made to conduct a biopsy 332 at the region ofinterest.

In accordance with one embodiment of the present invention (FIG. 11B),following the acquisition of a mammogram at step 300, the radiologistmay refer to both optical density data, and sound pattern data ascollected by a sound detector (step 311) in order to identify regions ofinterest within a patient's breast. Step 311 may additionally comprisecomparing sound pattern data obtained from a first of a patient'sbreasts to the sound data obtained from the patient's contralateralbreast. The comparison can yield information relating to the blood flowcharacteristics of the respective breasts, and can yield a comparisonmetric that can in turn be applied to the analysis of the mammogramobtained at step 300. The additional data parameter of sound istherefore used to render more precise the step of identifying regions ofinterest. If the radiologist concludes that the region of interestrepresents normal tissue at step 321, no further action is taken.However, if the radiologist believes that the visual region of interestcould represent cancerous growth at step 323, a recommendation will bemade to conduct a biopsy 333 at the region of interest. It isanticipated that the number of unnecessary biopsies that are recommendedby the radiologist will become attenuated through the use of the sounddata parameter in combination with the optical density patterns presenton the mammogram.

CAD processes may be used to aid in the interpretation of mammograms,using specific algorithms to flag possible regions of interest forreview by a radiologist. In an embodiment of the present invention (FIG.12), the radiologist may refer to both optical density and sound patterndata as collected by a sound detector (step 315) in order to identifyregions of interest within a patient's breast. Step 315 may additionallycomprise comparing sound pattern data obtained from a first of apatient's breasts to the sound data obtained from the patient'scontralateral breast. The comparison can yield information relating tothe blood flow characteristics of the respective breasts, and can yielda comparison metric that can in turn be applied to the analysis of theCAD evaluation obtained at step 313. Additionally, the radiologist mayreview CAD-generated recommendations 313 as to possible regions ofinterest within the patient's breast. Based on these sources of data313, 315, the radiologist may make a diagnosis 325 as to the highlightedanatomical regions, which may be that the regions of interest representnormal tissue 335, or that they may be indicative of cancerous growth337. In the latter instance, the radiologist may recommend a biopsy 345on one or more of the regions of interest.

In accordance with the present invention, the CAD algorithms themselvesmay be tailored to process sound data, including a comparison metricthat results from the comparison of sound data from a first andcontralateral breast, respectively, as acquired at some time before,during, or after a mammogram 300 is acquired. Thus, as illustrated inFIG. 13, in addition to processing the data parameter of opticaldensities, the CAD algorithm may be structured to process data acquiredthrough sound detection and mark a mammogram to identify potentialregions of interest (317). The radiologist may also perform a visualanalysis of the mammogram 319, and review all potential regions ofinterest in order to make a diagnosis 327. The regions of interest maybe deemed normal tissue 338, or may be considered to be suggestive ofcancerous growth 339. In the latter instance, the radiologist mayrecommend a biopsy 347 on one or more of the regions of interest.

While the invention has been described and illustrated with reference tospecific embodiments, those skilled in the art will recognize thatmodifications and variations may be made without departing from theprinciples of the invention as described herein and set forth in thefollowing claims.

1. A method comprising: (a) securing a first compression devicecomprising an x-ray transparent inflatable chamber over a tube-sidesurface of a first breast of a patient positioned on an imaging area ofa bucky on a mammography unit; (b) at least partially filling theinflatable chamber of the first compression device with a fluid, therebycompressing the breast between the inflatable chamber and the imagingarea and at least partially occluding blood flow to the breast; (c)transmitting x-rays through the breast; (d) releasing at least a portionof the fluid from the inflatable chamber, wherein the release of thefluid from the chamber controls the resumption of blood flow to thebreast; (e) detecting sounds generated by the resumption of blood flowto the breast; and, (f) repeating each of said steps (a)-(e) withrespect to said patient's contralateral breast.
 2. The method accordingto claim 1 further comprising detecting sounds within said first breastand said contralateral breast when said breasts are not compressed. 3.The method according to claim 2 comprising detecting sounds within saidfirst breast and said contralateral breast prior to at least partiallyfilling the inflatable chamber of the first compression device.
 4. Themethod according to claim 2 comprising detecting sounds within saidfirst breast and said contralateral breast following said releasing ofthe fluid from the inflatable chamber and after blood flow to therespective breast has been substantially completely restored.
 5. Themethod according to claim 1 further comprising securing a secondcompression device comprising an x-ray transparent inflatable chamberover the imaging area of the bucky, and at least partially filling theinflatable chamber of the second compression device with a fluid,thereby compressing said first breast and said contralateral breast,respectively, between the inflatable chamber of the second compressiondevice and the first compression device.
 6. The method according toclaim 1 further comprising administering to said patient an x-ray-opaquecontrast agent prior to releasing at least a portion of the fluid fromthe inflatable chamber.
 7. The method according to claim 6 furthercomprising transmitting x-rays through said first breast and saidcontralateral breast after releasing at least a portion of the fluidfrom the inflatable chamber.
 8. The method according to claim 1 furthercomprising comparing said detected sounds from said first breast withsaid detected sounds from said contralateral breast.
 9. The methodaccording to claim 8 wherein said comparison provides a comparisonmetric, and further comprising using said metric during the analysis ofat least one of a computer-assisted detection process, a mammogram, or adatabase of mammography images.
 10. A method comprising: (a) securing afirst compression device comprising an x-ray transparent inflatablechamber over an imaging area of a bucky of a mammography unit, so thatwhen a first breast of a patient is positioned upon the imaging area,the breast is interposed between the first compression device and acompression surface positioned above a tube-side surface of the breast;(b) at least partially filling the inflatable chamber of the firstcompression device with a fluid, thereby compressing the breast betweenthe inflatable chamber and the compression surface and at leastpartially occluding blood flow to the breast; (c) transmitting x-raysthrough the breast; (d) releasing at least a portion of the fluid fromthe inflatable chamber, wherein the release of the fluid from thechamber controls the resumption of blood flow to the breast; (e)detecting sounds generated by the resumption of blood flow to thebreast; and (f) repeating each of said steps (a)-(e) with respect tosaid patient's contralateral breast.
 11. The method according to claim10 wherein said compression surface is a paddle.
 12. The methodaccording to claim 11 further comprising securing a second compressiondevice comprising an x-ray transparent inflatable chamber to saidpaddle, and at least partially filling the inflatable chamber of thesecond compression device with a fluid, thereby compressing said firstbreast and said contralateral breast, respectively, between theinflatable chamber of the second compression device and the firstcompression device.
 13. The method according to claim 10 furthercomprising detecting sounds within said first breast and saidcontralateral breast when said breasts are not compressed.
 14. Themethod according to claim 10 further comprising detecting sounds withinsaid first breast and said contralateral breast prior to at leastpartially filling the inflatable chamber of the first compressiondevice.
 15. The method according to claim 10 further comprisingdetecting sounds within said first breast and said contralateral breastfollowing said releasing of the fluid from the inflatable chamber andafter blood flow to the respective breast has been substantiallycompletely restored.
 16. The method according to claim 10 furthercomprising comparing said detected sounds from said first breast withsaid detected sounds from said contralateral breast.
 17. The methodaccording to claim 16 wherein said comparison provides a comparisonmetric, and further comprising using said metric during the analysis ofat least one of a computer-assisted detection process, a mammogram, or adatabase of mammography images.
 18. A method comprising: (a) securing afirst compression device comprising an x-ray transparent inflatablechamber to a compression paddle of a mammography unit having a buckywith an imaging area; (b) at least partially filling the inflatablechamber of the first compression device with a fluid, therebycompressing a first breast of a patient that is positioned on the buckybetween the inflatable chamber and the imaging area, and at leastpartially occluding blood flow to the breast; (c) transmitting x-raysthrough the breast; (d) releasing at least a portion of the fluid fromthe inflatable chamber, wherein the release of the fluid from thechamber controls the resumption of blood flow to the breast; (e)detecting sounds generated by the resumption of blood flow to thebreast; and, (f) repeating each of steps (a)-(e) with respect to saidpatient's contralateral breast.
 19. The method according to claim 18further comprising securing a second compression device comprising anx-ray transparent inflatable chamber over the imaging area of the bucky,and at least partially filling the inflatable chamber of the secondcompression device with a fluid, thereby compressing said first breastand said contralateral breast, respectively, between the inflatablechamber of the second compression device and the first compressiondevice.
 20. The method according to claim 18 further comprisingcomparing said detected sounds from said first breast with said detectedsounds from said contralateral breast.
 21. The method according to claim20 wherein said comparison provides a comparison metric, and furthercomprising using said metric during the analysis of at least one of acomputer-assisted detection process, a mammogram, or a database ofmammography images.
 22. A method comprising using a comparison of dataderived from the detection of Korotkoff sounds within a patient's firstbreast and data derived from the detection of Korotkoff sounds within apatient's contralateral breast to interpret a mammogram.
 23. The methodaccording to claim to 22 wherein said data is used to designate one ormore regions of interest on a mammogram.
 24. The method according toclaim 22 wherein said data is used during a computer-assisted detectionprocess.
 25. A method comprising: (a) compressing a first breast of apatient, whereby the resulting compression occludes at least some bloodflow to the breast; (b) at least partially relieving such compression,such that blood flow to the breast is at least partially restored; (c)detecting Korotkoff sounds within the breast; and, (d) repeating each ofsteps (a)-(c) with respect to said patient's contralateral breast. 26.The method according to claim 25 further comprising comparing saiddetected Korotkoff sounds from said first breast with said detectedKorotkoff sounds from said contralateral breast.
 27. The methodaccording to claim 26 wherein said comparison provides a comparisonmetric, and further comprising using said metric during the analysis ofat least one of a computer-assisted detection process, a mammogram, or adatabase of mammography images.
 28. The method according to claim 25comprising using data derived from the detection of Korotkoff soundswithin said first breast and said contralateral breast to designateregions of interest on a mammogram.
 29. The method according to claim 28wherein said data is used during a computer-assisted detection process.30. The method according to claim 25 further comprising transmittingx-rays through said first breast to obtain a first mammogram, andtransmitting x-rays through said contralateral breast to obtain a secondmammogram.